Receptors and signaling (complete) Flashcards
What are the three parts of the cell signaling cascade
- Reception
- Transduction
- Response
What is a transcription factor
a protein that interacts with DNA and increases/decreases transcription of specific genes
How specific are transcription factors
they are very specific, each transcription factor only influences the transcription of certain genes
what do protooncogenes do?
they act as positive regulators of cell growth. they induce tumors when they are overactive
What do tumor suppressors do
they act as negative regulators of cell growth. when they lose function tumor growth results
What are the four secondary messengers
- cAMP
- IP3
- DAG
- Calcium
What enzyme activates cAMP
adenylate cyclase
What enzyme activates IP3
phospholipase 3
What enzyme activates DAG
phospholipase 3
What is the process by which Ca++ is activated
IP3 is activated by phospholipase 3, then the IP3 goes on to activate Ca++
What is the structure of G protein-coupled receptors
a protein made of 3 subunits bound to a receptor
what are the three subunits of the G protein that is bound to the receptor
alpha
beta
gamma
Which protein subunit attaches the GDP
the alpha subunit
What happens first when the G protein coupled receptor binds a ligand
the GDP on the alpha subunit gets phosphorylated into GTP
What happens after the GDP on the alpha subunit of the G protein coupled receptor is phosphorylated into GTP
the alpha subunit dissociates from the beta and gamma subunits
What happens after the alpha subunit of the G protein-coupled receptor dissociates from the beta and gamma subunit
the activated alpha subunit goes and activates an enzyme
What are the steps involved in the G protein-coupled receptors messaging process
- receptor portion binds a ligand
- alpha subunit (while associated with the beta and gamma subunit) has its GDP phosphorylated into GTP
- the alpha subunit dissociates from the beta and gamma subunit
- the activated alpha subunit goes and activates an enzyme. (adenylate cyclase or phospholipase 3)
A. if it activates adenylate cyclase then it will produce cAMP (secondary messenger)
B. if it activates phospholipase 3 then it will produce DAG and IP3 (secondary messengers)
C. IP3 may then go on to activate Ca++ (secondary messenger)
is Receptor Tyrosine Kinase an enzyme or a receptor
BOTH
what happens when one receptor tyrosine kinase binds a ligand
nothing. It has to wait until the adjacent receptor tyrosine kinase binds a ligand as well
What happens when two adjacent receptor tyrosine kinases each bind a ligand
then the receptor tyrosine kinases will dimerize (come together) and then they are activated
What is on the intracellular portion of the receptor tyrosine kinase
3 tyrosine spots which can easily be phosphorylated
What is a first messenger
a ligand or hormone that begins cellular messenging
How many ATPs are needed to completely phosphorylate a receptor tyrosine kinase dimer
6 ATPs are needed
What are the steps involved in the receptor tyrosine kinase cellular messaging process
- BOTH receptor tyrosine kinases bind a ligand
- the receptor tyrosine kinases dimerize (come together)
- 6 ATPs phosphorylate the tyrosine locations
- The activated receptor tyrosine kinases initate a cellular response
